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Neurophysiology > Unit 3 > Flashcards

Unit 3 Flashcards

1
Q

Describe sound

A

Sound is a vibration that propagates as an audible mechanical wave of pressure and displacement

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2
Q

______ is what makes different instruments sound distinct even if they are playing the same pitch at the same intensity

A

Timbre (tone color, tone quality)

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3
Q

What are examples of timbre?

A

Overtones
Harmonics
Sound envelope

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4
Q

What are the components of the external ear?

A

Auricle (pinna)

Auditory canal

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5
Q

What is the function of the external ear?

A

Functions to gather sound toward the tympanic membrane

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6
Q

What are the components of the middle ear?

A

From ear drum to the oval window
Includes ossicles (malleus, incus and stapes)
Tympanic cavity
Auditory tube

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7
Q

What is the function of the middle ear?

A

Transfers sound energy to the oval window

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8
Q

What are the components of the inner ear?

A

Bony labyrinth
Membranous labyrinth
Cochlea
Vestibular system

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9
Q

_____ is the hollow cavity of the temporal bone

A

Bony labyrinth

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10
Q

______ and ______ are components in the membranous labrynth

A

Cochlea

Vestibular system

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11
Q

Cochlea functions in ______

Vestibular system functions in ______

A

Cochlea- sound detection

Vestibular system- balance detection

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12
Q

What is impedance matching?

A

due to the lever actions of the ossicles, the sound vibrations are transmitted to the round window with greater force

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13
Q

_________ is necessary because inner ear fluids have more inertia than air

A 
Impedance matching 
(The sound vibrations are transmitted to the round window with greater force)
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14
Q

What 2 muscles are involved in the attenuation reflex?

A

Tensor tympani and stapedius

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15
Q

______ and _____ dampen vibrations during chewing, speech and other loud noises

A

Tensor tympani and stapedius

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16
Q

What is the origin and insertion, innervation and function of tensor tympani?

A

O: auditory tube
I: malleus
Innervation: CN V3
Function: tenses the tympanic membrane

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17
Q

what is the origin, insertion, innervation and function of the stapedius?

A

O: pyramidal eminence of temporal bone
I: stapes
Innervation: CN VII
Controls amplitude of sound waves entering the inner ear

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18
Q

Describe the cochlea shape

A

3 adjacent fluid filled tubes coiled into a shell shape

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19
Q

What are the names of the 3 adjacent fluid filled tubes that make up the cochlea?

A 
Scala vestibuli (vestibular duct)
Scala media (cochlear duct)
Scala tympani( tympanic duct)
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20
Q

________ is a component of the cochlea that is thin and easily moves with sound vibrations

A

Scala vestibuli (vestibular duct)

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21
Q

_______ is a component of the cochlea that contains the organ of Corti

A

Scala media (cochlear duct)

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22
Q

______ is a component of the cochlea that ends at the round window and functions to connect to the scala vestibuli at the helicotrema

A

Scala tympani (tympanic duct)

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23
Q

What component of the cochlea contains endolymph?

A

Scala media (cochlear duct)

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24
Q

What components of the cochleae contain perilymph?

A 
Scala vestibuli (vestibular duct)
Scala tympani(tympanic duct)
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25
Q

What are the 2 membranes that separate the 3 tubes of the cochlea?

A 
Vestibular membrane (Reissner’s membrane)
Basilar membrane
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26
Q

_______ is located between the scala vestibuli and the scala media

A

Vestibular membrane (Reissner’s membrane)

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27
Q

_______ is located between the scala media and the scala tympani

A

Basilar membrane

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28
Q

______ contains hair cells

A

Organ of Corti

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29
Q

Where does the organ or Corti lie?

A

On top of the basilar membrane

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30
Q

What are the Mechanoreceptors for sound called And where are they located?

A

Hair cells

Organ of Corti

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31
Q

What are the nerve fibers that are formed by stimulation of hair cells?

A

Cochlear nerve

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32
Q

What are the hair cell embedded in?

A

The tectorial membrane

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33
Q

Describe the distribution of sound as it hits the tympani membrane causing it to vibrate

A

Tympanic membrane -> auditory ossicles transmit sound to the faceplate of stapes at oval window -> vibration of perilymph and endolymph

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34
Q

The _______ vibrates at different points depending on the frequencies of sound present

A

Basilar membrane

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35
Q

Basilar membrane contains _______ that are shorter and stiffer near the oval window and longer and flexible near the helicotrema

A

Reed-like fibers

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36
Q

______ that vibrate on the basilar membrane stimulate local hair cells

A

The reeds (reed-like fibers)

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37
Q

Reed like fibers are shorter and stiffer near the ______ ; longer and flexible at the ________

A

Oval window

Helicotrema

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38
Q

High frequencies (short wavelengths) is detected near the _________ , low frequencies toward the _______

A

Oval window; helicotrema

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39
Q

What is the function of the round window?

A

Helps dissipate the pressure within the inner ear. Bc the cochlea is embedded in bone which is unyielding

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40
Q

Round window bulges in and out wiht the vibrations caused by the _______

A

Stapes

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41
Q

What are the differences of the internal hair cells and external hair cells

A

Internal hair cells- fewer of them. Primary receptors for hearing
External hair cells - more numerous. In some way control the sensitivity of the inner hair cells

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42
Q

____ are the primary receptors for hearing

A

Internal hair cells

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43
Q

What is the function of external hair cells?

A

In some way control the sensitivity of the inner hair cells

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44
Q

The hairs themselves in the organ of Corti are called _______

A

Stereocilia

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45
Q

Describe the hair cell function

A

As the basilar membrane fibers move up and down the reticular lamina rocks back and forth making the stereocilia that is embedded in the tectorial membrane bend

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46
Q

Bending of the stereo cilia in one direction cause ______ and in the other direction cause _______

A

Depolarization; hyperpolarization

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47
Q

______ and _________ contain perilymph

A

Scala vestibuli and scala tympani

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48
Q

________ communicates with the subarachnoid space around the brain and the composition is similar to CSF

A

Perilymph

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49
Q

_______ contains endolymph

A

Scala media

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50
Q

What secretes endolymph?

A

Stria vascularis of the tunica media

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51
Q

What is the composition of endolymph? Perilymph?

A

Endolymph: high concentration of K and low Na (the opposite of perilymph)
Perilymph: composition similar to CSF

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52
Q

Loudness detection is based on what?

A

Amplitude of vibration of the basilar membrane

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53
Q

What occurs to the hair cells with louder noises?

A

More inner hair cells on the fringes of the basilar membrane are stimulated causing spatial summation
More outer hair cells get stimulated as well

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54
Q

______ is how sound intensities are expressed in terms of the log of their actual intensities

A

Decibel Unit

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55
Q

A 10X increase in sound energy is called __________ and _______ is called a decibel

A

1 bel

.1 bel is called a decibel

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56
Q

________ sounds must be loud to be heard. ________ sounds can be heard at much lower amplitudes (frequency)

A

Low frequency

High frequency

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57
Q

After hair cells are stimulated, they synapse with _______

A

Spiral ganglion cells (bipolar)

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58
Q

The axons from the spiral ganglion form the ______ nerve

A

Cochlear part of the vestibulocochlear nerve. (Aka auditory nerve)

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59
Q

Axons of the cochlear nerve terminate where?

A

In both the dorsal and ventral cochlear nuclei in the medulla

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60
Q

In the auditory pathway, What directions can the secondary afferents project following synapsing at the cochlear nuclei?

A

1) cross over via the trapezoid body to the contralateral superior olivary nucleus then enter the lateral lemniscus
OR
2) ascend ipsilaterally into the lateral lemniscus

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61
Q

The lateral lemniscus terminates mostly into the ________ but also some fibers terminate in the _______

A

Inferior colliculus ; geniculate nucleus

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62
Q

________ is the sensory relay center for auditory input

A

Medial geniculate nucleus

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63
Q

Neurons from the medial geniculate nucleus travel through the ______ to terminate in the ________

A

Auditory radiations to terminate in the primary auditory complex of the temporal lobe

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64
Q

The secondary afferents of the auditory pathway can ascend ipsilateral into the _______ OR cross over via the _______ to the contralateral _________ then enter the _______

A

Lateral lemniscus

Trapezoid body; superior olivary nucleus; lateral lemniscus

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65
Q

Give a summary of the auditory pathway

A

Axons of the cochlear nerve -> dorsal and ventral cochlear nuclei in the medulla -> either cross over and go to the trapezoid body -> superior olivary nucleus to reach the lateral lemniscus or ascend ipsilateral to reach the lateral lemniscus
From lateral lemniscus -> mostly into the inferior colliculus and some to the medial geniculate nucleus
From medial geniculate nucleus -> auditory radiations -> Primary cortex of the temporal lobe

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66
Q

What are the 2 components of the auditory cortex?

A

Primary auditory cortex

Auditory association cortex

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67
Q

The Primary auditory cortex is brodmanns area _______. It is located in the ______.

A

41

Located in the superior temporal gyrus

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68
Q

_________ is where generally lower frequency sounds are processed anteriorly and other aspects of sounds are processed as well such as direction and onset of sounds

A

Primary auditory cortex (brodmanns area 41)

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69
Q

Direction and onset of sounds are processed in the ______

A

Primary auditory cortex

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70
Q

The auditory association cortex is located ________

A

Peripherally to the primary cortex in the temporal lobe and insula

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71
Q

Where is the meaning of sound processed?

A

Auditory association cortex

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72
Q

________ is necessary for speech interpretation

A

Wernicke’s area

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73
Q

________ is the ability to tell wher sounds are coming from

A

Direction discrimination

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74
Q

What are the two mechanisms of direction discrimination?

A

Time lag between the two ears

Difference in sound intensities from the two ears; sound is more muffled coming from the opposite side

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75
Q

Time lag between the two ears mechanism of direction discrimination is less helpful for sounds directly infront, behind or above a person. And is compensated by ________

A

Pinna facing forward

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76
Q

Direction discrimination of sound is largely processed in the ________

A

Superior olivary nuclei

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77
Q

In centrifugal signals, There are efferent fibers from ________ that send inhibitory signals to the _________.

A

Superior olivary nucleus ; hair cells in the organ of Corti

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78
Q

_______ produced from efferent fibers from superior olivary nucleus that sends inhibitory signals to the hair cells of the organ of Corti are thought to ________ certain sounds to help pick out tunes of interest

A

Centrifugal signals

Tune out

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79
Q

What are two types of deafness?

A

Nerve deafness and conduction deafness

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80
Q

Describe nerve deafness

A

Loss of hearing due to damage to the cochlea, cochlear nerve or parts of the CNS involved with hearing

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81
Q

Complete destruction of the cochlea or its nerve causes _______

A

Permanent nerve deafness

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82
Q

Describe Conduction deafness. And how is damage acquired?

A

Loss of hearing due to damage to the tympanic membrane or ossicles
Damage is often due to calcification or fibrosis

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83
Q

In conduction deafness the ______ is still possible as long as the cochlea is intact

A

Bone conduction

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84
Q

In age related nerve deafness what occurs?

A

A person’s bone conduction is a little less than air conduction and higher wavelengths are more effected.

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85
Q

_______ can occur due to middle ear sclerosis

A

Conduction deafness

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86
Q

In conduction deafness, the bone conduction is normal. Why?

A

Bc the cochlea is NOT damaged and can hear vibrations directly plied to the bone surrounding it

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87
Q

In conduction deafness, _______ is diminished due to the inability of the middle ear structures to transmit sound

A

Air conduction

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88
Q

What tests can be used to distinguish nerve vs conduction deafness

A

Rinne’s test

Weber’s Test

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89
Q

Normally sound stops being heard behind the ear on the ________, moving the tuning fork next to the ______ can be heard again

A

Mastoid

Meatus

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90
Q

In the _______ the tuning fork should be louder infront of the ear rather than behind it near the mastoid.

A

Rinne’s test

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91
Q

________ detects lateralization of sound. ( can you hear a buzzing noise when the tuning fork is placed midline?

A

Weber’s test

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92
Q

To test hearing hearing loss, _______ test tests for conduction and _______ test tests for localization

A

Conduction - rinne’s test

Localization - Weber’s test

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93
Q

There is no hearing loss when in the rinne’s test there is ______ and in the Webers test there is ______

A

Rinne’s test - air is greater than bone

Weber test - midline

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94
Q

Taste is primarily a function of ________, although taste experience is influenced by: ______, ______ and _____

A

Taste buds

Smell, tactile stimulation of tongue, chemical irritants such as capsaicin

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95
Q

What are the 5 categories of taste modalities?

A 
Sour 
Salty 
Sweet
Bitter
Umami
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96
Q 
What do the following taste modalities respond to?
Sour
Salty
Sweet
Bitter
Umami
A

Sour- acids
Salty- ionized salts, mainly sodium
Sweet- sugar, glycols, alcohols, aldehydes, ketones, sulfonic acids
Bitter- long chain organic nitrogen containing molecules, alkaloids (drugs and plant toxins)
Umami- L-glutamate (MSG)

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97
Q

Taste buds are located within a large structure called _____

A

Papilla

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98
Q

Taste buds are composed of ________ clustered under a _______. These cells have _______ on their apical surfaces

A

Chemosensitive cells clustered under a taste pore.

These cells have taste hairs on their apical surface (microvilli)

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99
Q

What are the 3 papillae that have taste buds and their locations?

A

Circumvallate (vallate) papillae - V shaped line on posterior tongue
Fungiform- folate anterior surface of the tongue
Foliate - lateral folds of tongue

There re also some buds on the palate and tonsils

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100
Q

_______ papillae do not have tase buds and are the most numerous

A

Filiform

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101
Q

T/F: certain taste buds respond to certain or specific taste modalities

A

False. Taste buds are more integrated throughout the tongue than previously thought

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102
Q

Chemicals specific to a taste bud will bind to receptors on the taste cells and cause opening of ion channels. This depolarizes the membrane creating a _______

A

Receptor potential

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103
Q

_____ washes away the chemical to remove the stimulus from the taste bud

A

Saliva

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104
Q

Describe accommodation in the taste buds

A

Afferent fibers from taste buds accommodate rather rapidly o that the taste sensation tapers off after the initial stimulation

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105
Q

What is the taste pathway of the anterior 2/3 of tongue?

A

Lingual -> chorda tympani branch-> facial nerve -> tractus solitarius (solitary nucleus)

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106
Q

What is the taste pathway from the posterior 1/3 of tongue

A

CN IX-> tracts solitarius (solitary nucleus)

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107
Q

Describe the taste pathway of the base of the tongue and pharynx

A

Vagus nerve -> tractus solitarius

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108
Q

Where do the second order neurons travel from the tractus solitarius?

A

Go to the VPM of the thalamus just medial to where fine touch from face terminates

109
Q

Where do third order neurons in the taste pathway go to?

A

The lower tip of the post central gyrus in the parietal cerebral cortex (gustatory cortex)

110
Q

What are other connections from the tractus solitarius other than the VPM?

A

Superior and inferior salivatory nucleus which triggers salivation

111
Q

Describe the taste pathway in general.

A

First order neruons come from chorda tympani (CN VII), CN IX, and CN X -> second order neurons to solitary nucleus -> either the superior or inferior Salvatory nucleus (salivation) OR -> VPM of thalamus.
From VPM of thalamus -> post central gyrus in the parietal cerebral cortex (gustatory cortex)

112
Q

Where does smell/ the olfactory system lie in te nose?

A

Superior part of each nostril

113
Q

The olfactory epithelium, the membrane contains what?

A

Bipolar olfactory cells which have cilia that project into the nasal cavity

114
Q

_______ glands secrete mucus in the nose

A

Olfactory glands (Bowmans glands)

115
Q

Describe olfactory cell depolarization

A

Odorant chemicals dissolve in the mucus then contacts cilia -> receptors on cilia use cAMP second messenger system to open ion channels -> depolarization of membrane

116
Q

Olfactory cells adapt by about _______ in a few seconds then gradually adapt further until _______

A

50%

The odor is no loner detected

117
Q

in the olfactory pathway, The olfactory cells axons penetrate the _______ and synapse in the olfactory bulb in regions called _______

A

Cribriform plate

Glomeruli

118
Q

In the olfactory pathway the receptors of the same specificity all converge on the same _______

A

Glomerulus

119
Q

In the olfactory pathway, axons leaving the glomerulus synapse with secondary neurons (_____ and ____ cells)

A

Tufted and mitral cells

120
Q

Axons from _____ and _____ form the olfactory tract that goes to the CNS

A

Tufted cells

Mitral cells

121
Q

The olfactory tract ends in one of the following 3 pathways, ______ , ______ or ______

A

Primitive olfactory system
Less old olfactory system
New pathway

122
Q

________ system has to do with response to smell such as salivation and feeding responses

A

Primitive olfactory system (medial olfactory area)

123
Q

What is the location of the primitive olfactory system (medial olfactory area)?

A

Septal nuclei anterior to the hypothalamus

124
Q

What is the location of the less old olfactory system (lateral olfactory area)?

A

Pyriform cortex of temporal lobe and amygdala

125
Q

What is the function of the less old olfactory system and what is another name for it?

A

Lateral olfactory system

Discriminates between tasteful and distasteful foods, memory of bad experience with a food

126
Q

Describe the new pathway of the olfactory pathway

A

Some fibers pass through thalamus then project to the paleocortex in the anteriomedial portion of the temporal lobe

Probably helps with conscious analysis of odors

127
Q

Sensory information is integrate and used to generate appropriate motor responses at 3 basic levels. What are those levels and what occurs at them?

A

Spinal cord - simple reflexes
Brain stem - more complex responses
Brain - complicated muscle skills

128
Q

In cord reflexes, sensory signals enter the _______ then divides into 2 branches; one transmits signals to _____ and the other ______

A

Higher levels of CNS

Terminates in SC for local reflexes

129
Q

What are the cells involved in cord reflexes?

A

Interneurons - integrative function of SC
Anterior motor neurons - gives rise to the fibers then leave the ventral roots in 2 types, alpha motor neurons and gamma motor neurons

130
Q

What are the two types of fibers involved in anterior motor neurons ventral roots?

A

Alpha motor neurons

Gamma motor neurons

131
Q

Alpha motor neurons have the _____ fiber type

A

Aalpha

132
Q

_______ neurons branch multiple times as they enter skeletal muscles they innervate. Innervate a motor unit.

A

Alpha motor neurons

133
Q

Axons of motor neruons extend from the ______ to the ______. There each axon divides into a number of _______ that form neuromuscular junctions with muscle fibers scattered throughout the muscle

A

SC -> muscle

Axon terminals

134
Q

What are the characteristics of gamma motor neurons?

A

About 1/2 as numerous as alpha motor neurons

Transmit Agamma fibers and they innervate intrafusal fibers which are important for controlling muscle tone

135
Q

Gamma motor neurons transmit through ____ fibers and they innervate special muscle cells called ______

A

Agamma ; Intrafusal fibers

136
Q

What are intrafusal fibers important for?

A

Controlling muscle tone

137
Q

Each muscle spindle contains _______ fibers that has both motor ____ and sensory _____ innervation

A

Intrafusal skeletal muscle fibers
Agamma
Ia and II

138
Q

What are two types of intrafusal fibers?

A

Nuclear bag fiber

Nuclear chain fiber

139
Q

What are the types of sensory neuron fibers involved in muscle spindles?

A

Ia- primary afferent or annulospiral ending

II- secondary ending or flower spray ending

140
Q

Ia sensory neuron fibers in the muscle spindle are _______ or ______

A

Primary afferent or annulospiral ending

141
Q

II sensory neuron fiber in the muscle spindle is _______ or ______

A

Secondary ending or flower spray ending

142
Q

What are two responses of spindle sensory function?

A

Static stretch response

Dynamic stretch response

143
Q

______ is a spindle sensory function where gradual stretch causes both primary and secondary endings to fire in proportion to the stretch

A

Static stretch response

144
Q

________ is a spindle sensory function where stretch causes ONLY the primary endings respond dramatically

A

Dynamic stretch response

145
Q

In the static stretch response, _____ stretch causes ________ to fire in proportion to the stretch

A

gradual stretch causes Both Primary and secondary endings fire

146
Q

In the dynamic stretch response, _____ stretch causes ______

A

Sudden stretch causes ONLY the primary ending to respond dramatically

147
Q

_______ neurons innervate the ends of the muscle spindle cells

A

Gamma motor neurons

148
Q

The gamma motor neurons innervate the ends of the muscle spindle cells, therefore if they fire, it ______ tension in the center of the fiber where the _______ are

A

Increases

Sensory nerve endings are

149
Q

_______ are gamma motor neurons that mainly effect the nuclear bag fibers

A

Gamma dynamic

150
Q

______ are gamma motor neurons that mainly defect the nuclear chain fibers

A

Gamma-static

151
Q

What do gamma dynamic neurons mainly affect?

A

Nuclear bag fibers

152
Q

What do gamma static neurons mainly affect?

A

The nuclear chain fibers

153
Q

What is the muscle stretch reflex mechanism?

A

Muscle stretch-> increased afferent signals ->SC-> increased efferent output though alpha motor neurons -> muscle contracts -> firing rate of afferent sensory neuron decreases

154
Q

What are the 5 steps of the muscle stretch reflex pathway?

A

1) stretching of msucle spindle stimulates muscle spindles
2) activation of sensory neuron
3) information processing at motor neuron
4) activation of motor neuron
5) contraction of muscle which opposes the stretching of the muscle spindles

155
Q

The muscle stretch reflex pathway is _______

A

Monosynaptic

156
Q

What is the pathway of dynamic stretch responses?

A

Nuclear bag-> Ia afferent -> alpha motor neuron -> skeletal muscle (extrafusal)

157
Q

What is the pathway of static stretch receptors?

A

Nuclear chain -> II afferent -> alpha motor neuron -> skeletal muscle (extrafusal)

158
Q

With dynamic and static stretch response:

In ______ reflex functions to oppose sudden changes in muscle length And occurs in a few seconds

A

Dynamic

159
Q

in dynamic vs static stretch responses:

In ______, Reflex functions help to maintain a the muscle at the new length. This occurs after the ______

A

Static

Dynamic

160
Q

_________ helps to maintain the degree of muscle tone until the person decides to do something else with the muscle

A

Static stretch responses

161
Q

What is an important function of the spindles?

A

Damping / smoothing

162
Q

During normal msucle activity, when the _____ fibers contract, the _______ must also

A

Extrafusal

Intrafusal

163
Q

What would occur if the extrafusal fibers contracted by the intrafusal fibers didn’t?

A

Spindles would become flaccid and therefore lose its sensitivity to stretch
And
Damping function would be lost

164
Q

Reflex tests are used to asses the integrity of what?

A

The sensory and motor pathways to and from the SC, the cord itself and for certain neurological disorders

165
Q

_______ is an encapsulated afferent nerve ending that is embedded within tendons

A

Golgi tendon organ

166
Q

What stimulates the golgi tendon organ?

A

Increases in tension exerted on the tendon by the muscle or other force

167
Q

What is the afferent innervation of the golgi tendon organ?

A

Ib

168
Q

What are the functions of the dynamic and static reflexes in the golgi tendon reflex?

A

Dynamic: senses rapid changes in tension

Static: steady state response in proportion to muscle tension

169
Q

What is the pathway of the golgi tendon reflex?

A

Tension -> Ib-> interneurons -> inhibits anterior motor neurons (alpha and gamma motor neurons)

170
Q

What does the golgi tendon reflex prevent?

A

Excessive tension on a tendon that may cause damage to the muscle (tearing) or the tendon (avulsion)

171
Q

What are the functions of golgi tendon reflex?

A

Equalize contractive forces among muscle fibers so that the load is distributed more evenly

Prevents excessive tension on a tendon that may cause damage to the muscle (tearing) or the tendon (avulsion)

172
Q

_________ functions in conscious proprioception and the perception of body position

A

Dorsal column - MLS

173
Q

_______ functions in unconscious proprioception and carry information to the cerebellum to appraise the brain about instantaneous changes occurring in the muscles and tendons

A

Dorsal spinocerebellar tract

174
Q

What does the dorsal spinocerbellar tract do?

A

Carry information to the cerebellum to appraise the brain about instantaneous changes occurring in the muscle and tendons

175
Q

What are other names for the flexor reflex? (3)

A

Withdrawal reflex
Pain reflex
Nociceptive reflex

176
Q

Effect of the flexor reflex is most powerfully stimulated by ______

A

Pain

177
Q

If a limb is painfully stimulated, flexors are likely to ________

A

Contract to move the limb away from the stimulus

178
Q

If another part of the body besides a limb is stimulated by pain the muscles involved may not actually be _______ so therefore the better term would be _______ reflex

A

Flexors

Withdrawal

179
Q

______ reflex is polysynaptic

A

Flexor reflex or withdrawal reflex

180
Q

What is the polysynaptic path of the flexor reflex?

A

Nociception -> interneurons -> motor neurons

181
Q

What are two reflexes that may accompany the flexor reflex?

A

Reciprocal inhibition

Crossed extensor reflex

182
Q

Describe reciprocal inhibition

A

If the reflex causes flexion in a limb, there will also be inhibition of its antagonist (the extensor)

183
Q

________ is a flexor reflex in the left limb causes extension in the right limb

A

Crosses extensor reflex

184
Q

What are 4 more complex cord reflexes?

A

Positive supportive reaction
Steeping movements
Injury induced spasm
Muscle cramps

185
Q

______ is a cord reflex where pressure on the foot tends to cause reflexive extension against the pressure

A

Positive supportive reaction

186
Q

_______ is a cord reflex where much of the oscillating movements between the legs and arm swing is hard wired in the cord

A

Stepping movements

187
Q

__________ is a cord reflex where pain from a significant injury, such as a bone fracture, causes reflex sustained contraction of muscles near the fracture

A

Injury induced spasm

188
Q

_______ causes a similar phenomenon of injury induced spasm involving spasm of the abdominal muscles

A

Peritonitis

189
Q

_______ is a cord reflex where local irritating factor ( metabolic issue, severe cold, ischemia, over exercise etc.) case contraction which exacerbates the irritation leading to a positive feedback situation called a ______

A

Muscle cramp

Cramp

190
Q

What are some examples of autonomic reflexes in the cord?

A

Changes in vascular tone resulting from changes in skin heat
Sweat reflex due to surface heat
Intestinointestinal reflexes that control gut motility
Evacuation reflexes fr emptying the full bladder or colon

191
Q

Most voluntary movements initiated by ______ are achieved when the cortex activated patterns of function stored in _________ - ___________. These ______ in turn send specific control signals to the muscles

A

Cerebral cortex
Lower brain areas - cord, brain stem, basal ganglia, cerebellum
Lower centers

192
Q

_______ occupies about 1/3 of the frontal lobe

A

Motor cortex

193
Q

The motor cortex occupies about 1/3 of the ______ lobes

A

Frontal

194
Q

What are the 3 parts of the motor cortex?

A

Primary motor cortex
Premotor area
Supplementary motor area

195
Q

What is the location of the primary motor cortex?

A

Pre central gyrus

Brodmanns area 4

196
Q

In the primary motor cortex, the inferior body is controlled toward the _______ and the head is controllled toward the ______

A

Longitudinal fissure

Horizontal fissure

197
Q

The primary motor produces _________ when stimulated

A

Discrete muscle movements

198
Q

Large pyramid cells called ______ make up outgoing cells from layer V of the cortical layers of the primary motor tract

A

Beta cells

199
Q

what are Betz cells

A

Large pyramidal cells that are outgoing cells from layer V

200
Q

What are some characteristics of Betz cells?

A

Only 3% of outgoing fibers
Largest, fastest
Appear to be involved with direct connections with lower motor neurons (neuron that leaves the SC through the ventral root)

201
Q

What is the location of the premotor area of the motor cortex

A

Anterior to the primary motor cortex

202
Q

Describe the topographical map of the premotor area

A

Head - inferior and lateral

Lower body- superior and medial

203
Q

________ generates more complex patterns of movement than the primary cortex

A

Premotor area

204
Q

What are the connections (3) that the premotor area has?

A

Basal ganglia
Thalamus
Primary motor cortex

205
Q

What is the location of the supplementary motor area of the motor cortex?

A

Mainly in the longitudinal fissure but extends somewhat onto the superior frontal cortex

206
Q

_______ works with the premotor area to produce bilateral body wide coordinated movements such as positioning the body as background for more fine motor control of the hands

A

Supplemental motor area

207
Q

________ is the motor speech area. It coordinates the muscles of the mouth, tongue and respiration adn larynx for speech

A

Broca’s area

208
Q

_______ allows selecting new fixation points consciously

A

Voluntary eye field and head rotation

209
Q

Loss of this area leads to motor apraxia. What is this area?

A

Hand skills

210
Q

What are the motor pathways?

A

Corticospinal (pyramidal) tract

“Extrapyramidal” tract

211
Q

What motor pathway tract is for detailed skilled movements particularly of distal limbs, this more direct pathway from brain to spinal cord is used

A

Corticospinal (pyramidal) tract

212
Q

What motor pathway invovles motor signals that descend from the brain and involve the basal ganglia, cerebellum or brain stem for muscle control

A

Extra pyramidal tracts

213
Q

________ tract is a motor pathway thats more for postural or generalized movements

A

Extra pyramidal tracts

214
Q

The extrapyramidal tracts involves motor signals that descend from the brain and involve ______, __________ or ______ for muscle control

A

Basal ganglia, cerebellum, brain stem

215
Q

In the cortex, the upper motor neurons of the corticospinal tract originate:

  • 30% from _______
  • 30% from ________ and ________
  • 40% from _________
A

Primary motor cortex
Premotor and supplementary motor cortex
Somatosensory association areas

216
Q

Regarding the corticospinal tract:

The upper motor neuron axons pass through the _______ -> _______ -> ______-> _______(medulla)

A
  • Posterior limb of internal capsule
  • cerebral peduncle (midbrain)
  • longitudinal fasciculus of pons
  • pyramids (medulla)
217
Q

Regarding the corticospinal tract:
In the caudal medulla most fibers decussate then descend in the ______ tracts of the cord.
A few fibers do not decussate and descend via the ______ tract

A

Decussate - lateral corticospinal tracts

Do not decussate - ventral corticospinal tract

218
Q

The few fibers that do not decussate and travel down the ventral corticospinal tract are for _____ (function)?

A

For bilateral posture movements controlled by the supplementary motor cortex

219
Q

The upper motor neuron of the corticospinal tract terminates mostly on _____ in the _____.

A

Interneurons

Cord

220
Q

The _________ neurons of the corticospinal tract synapse with the _________ neurons

A

Upper motor neurons

Lower motor neurons

221
Q

Some cortical motor fibers terminate in the _________ (midbrain) via the _______ tract

A

Red nucleus

Corticorubral tract

222
Q

Some cortical motor fibers terminate in the red nucleus via the corticorubral tract then fibers descend to the _______ of the spinal cord via the ________

A

Interneurons of the SC via the rubrospinal tract

223
Q

________ tract appears to be accessory to the lateral corticospinal tracts

A

Rubrospinal tract

224
Q

Describe somatosensory feedback

A

Input from muscle spindles and golgi tendon organs as described earlier
Tactile input triggers grasping motions or pressure on feet cause extension motions

225
Q

________ reflex is important in helping “dampen” the motor movements initiated by the cerebral cortex. Part of the. Motive power is due to stimulation of the ______ reflexes

A

Stretch reflex

Spindle reflexes

226
Q

Brain initiated motor movements to muscles is not accompanied by brain initiated inhibition to antagonistic muscles bc _________ reflex does it automatically

A

Spinal cord’s reciprocal inhibition reflex

227
Q

Cord withdraw, walking, postural, scratch reflexes etc. can be activated by what?

A

Commands coming from the brain

228
Q

What are examples of autonomic control of the brainstem control of motor function?

A

Respiration
Cardiovascular
Some GI

229
Q

What are the examples of brainstem control of motor function (3)?

A

Autonomic control

Motor functions involving the reticular nuclei (pontine and medullary) and the Vestibular nuclei

230
Q

What are the two reticular nuclei?

A

Pontine reticular nuclei

Medullary reticular nuclei

231
Q

________ reticular nuclei excite antigravity muscles, gives rise to medial reticulospinal tract

A

Pontine reticular nuclei

232
Q

The pontine reticular nuclei gives rise to __________ tract

A

Medial (pontine) reticulospinal tract

233
Q

_________ nuclei work with the vestibular system which is also excitatory

A

Pontine reticular nuclei

234
Q

Medullar reticular nuclei inhibit _______

A

Antigravity muscles

235
Q

Medullary reticular nuclei gives rise to _________ tract

A

Lateral (medullary) reticulospinal tract

236
Q

What tracts do the medullary reticular nuclei work with to allow voluntary override of the postural muscle activity

A

Corticospinal and rubrospinal tracts

237
Q

______ reticular nuclei excite antigravity muscles

______ reticular nuclei inhibits antigravity muscles

A

Pontine

Medullary

238
Q

______ nuclei are excitatory to postural muscles but is selective as to which muscles it excites based on input from the ______ system

A

Vestibular nuclei

Vestibular system

239
Q

_______ and ______ contain sensory structures called maculae that have hair cells that are embedded in a gelatinous structures containing otoliths (statoconia) made of calcium carbonate

A

Utricle and saccule

240
Q

The utricle and saccule contain sensory structures called _____ that have hair cells embedded in a gelatinous structure containing _______ made of calcium carbonate

A

Maculae; otoliths (statoconia)

241
Q

Gravity pulls of these ______ therefore bending the hair cells in the utricle and saccule

A

Otoliths

242
Q

The utricle senses static position of the head in respect to gravity best in the ______ position

A

Upright

243
Q

The saccule sense static position of the head in respect to gravity best in the ______ position

A

Horizontal

244
Q

The ______ and ______ detect linear acceleration

A

Utricle and saccule

245
Q

In the _____ of each semicircular duct is a _______ with hair cells embedded in the sail- like structure called the ______

A

Ampulla; cristae ampullaris; cupula

246
Q

Describe the semicircular duct orientations

A

Each duct is oriented to a different sagittal plane ( anterior, posterior and lateral (horizontal))

247
Q

During rotational movement of the head, fluid due to inertia will not move while the membranes of the ducts move with the head. This bends the _______ and bends the ______

A

Cupula ; hair cells

248
Q

What are semicircular ducts good at detecting?

A

Head rotation, angular acceleration, and prediction of malequillibrium

249
Q

Describe vestibular postural reflexes

A

Sudden changes in orientation causes motor movement to “right” the orientation

250
Q

Describe the vestibular postural reflex as a part of eye stabilization

A

Movement of the head counterbalances by movement of the eyes to keep them fixated on target

251
Q

What are 4 other mechanisms that influence equillibrium

A

Neck proprioception
Body proprioception
Exteroreception
Visual information

252
Q

_______ counterbalances the vestibular signals when the head is tilted but the body is upright

A

Neck proprioception

253
Q

________ is involved in detecting weight distribution between feet and weight distribution between hindfoot and forefoot

A

Body proprioception

254
Q

_________ is when feeling of wind on body causes one to lean a into it to keep balance

A

Exteroception

255
Q

___________ can compensate for loss of equillibrium by neck proprioception, body perception and exteroception as long as the eyes are open

A

Visual information

256
Q

In regards to the vestibular pathway:
Vestibular nerves from the vestibular apparatus -> ______ there it can pass to 3 different possible locations in the CNS

A

Vestibular nuclei

257
Q

What are 3 examples of paths from the vestibular nuclei in the vestibular pathway?

A

Vestibular nuclei -> vestibulospinal tracts

Vestibular nuclei -> medial longitudinal fasciculus -> CN III, IV, VI (eye movement)

Vestibular nuclei -> parietal lobe by lateral fissure

258
Q

What are the 4 vestibular nuclei?

A

Superior
Medial
Lateral
Inferior

259
Q

What are the inputs to the superior and medial vestibular nuclei? Outputs?

A

Afferents from semicircular ducts

Efferent to eyes, neck, and head muscles

260
Q

What is the function of the superior and medial vestibular nuclei?

A

Function to position head and eyes to correct for changes in equilibrium

261
Q

What are the inputs and outputs of the lateral vestibular nuclei?

A

Input from utricle and saccule

Output to body

262
Q

What is the function of the lateral vestibular nuclei?

A

To control righting reflexes of the body

263
Q

What are the inputs and outputs of the inferior vestibular nuclei?

A

Input from the semicircular canal, utricle and saccule

Output to cerebellum and reticular formation

264
Q

What is the function of the inferior vestibular nuclei?

A

Coordinates the function of the vestibular system with these motor control areas

265
Q

When looking at sound waves, the crests correspond with _______; the throughs correspond with _________.

A

crests- compression

Troughs- rarefraction (decompression)

266
Q

The shorter the wavelength the higher the _______ and the higher the _____

A

Frequency and pitch

267
Q

The higher the amplitude of sound, the __________ it is

A

Louder

268
Q

______ functions in inhibition of hearing or in other words “selective hearing”

A

Centrifugal signals

Neurophysiology (4 decks)

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